Tadpole study finds cannibalism dangerous to health

It may be possible to equate the study of cannibalism in tadpoles to the effects of climate change and over-population, and that is just what researchers at the University of Saskatchewan in Canada have done.

Many North American species of frogs, salamanders and other kinds of amphibians occasionally resort to cannibalizing their own when other resources are scarce. Researchers wondered if tadpoles really actually avoided the option of eating their own, or used it as a last resort.

The team of researchers decided that, theoretically, eating the meat of one's own species would be the most nutritionally sound thing to do because it contained the vitamins and nutrients necessary to physiological health. But when would tadpoles resort to eating their own kind, and would they prefer to eat tadpole meat over other sources of food?

Study co-author Dale Jefferson told Live Science,"Any species that is the same as your own would theoretically be an ideal diet because they are going to contain all of the nutrients that you require for growth and development, in supposedly the correct proportions. You can basically get everything you need from one source."

Feeding experiments were done using different combinations of frozen brine shrimp, cornmeal, tadpole meat or no food at all. In the wild, tadpoles will eat algae and other small aquatic animals when not eating each other.

The team found the tadpoles chose to eat the brine shrimp meat because of the protein content, leaving the cornmeal. The tadpoles ate the tadpole meat when under conditions of starvation or when there was competition for food. It was decided the brine shrimp had almost the same protein content as tadpole meat.

The team noted that there are a number of downsides to cannibalism, especially when members of the same species cannibalize each other, causing death and injuries. Along the same line of thought, from an evolutionary standpoint, this behavior could easily limit the gene pool when cannibalism is taking place.

The spread of pathogens is more prevalent with cannibalism because members of the same species are susceptible to the same pathogens, while more distant members of that species will often not catch the same types of infections.

Jefferson notes that the research is timely now because in Canada, many of the ponds used in the study are now dried up, possibly as a result of climate change. This means that as ponds continue to dry up, remaining ponds will become more densely populated, creating overcrowding and competition for food. Cannibalism could potentially increase, raising the risk of increased infectious diseases.

The results of the study were published on February 18 in the journal, Naturwissenschaften.